Doesn't look like they charter out of Florida.. but they have some really good prices. I was surprised, on the website.. looks like for an older Leopard 42 for 21 days right around $10K, discounted from $14K.
Fun in the Sun yacht charters out of Fort Lauderdale. They have a couple of L440s and may give you a deal on a 4 week charter. There is a newish base for Dream Yachts charters also in Fort Lauderdale. Have fun.